Final answer:
The potential adverse effect of hydrochlorothiazide is hypokalemia, which is a decrease in potassium levels in the blood.
Step-by-step explanation:
The potential adverse effect of hydrochlorothiazide is hypokalemia, which is a decrease in potassium levels in the blood. Hydrochlorothiazide is a diuretic medication that increases the excretion of water and electrolytes, including potassium, from the body. This can lead to an imbalance in potassium levels. Hypokalemia can cause symptoms such as muscle weakness, fatigue, and irregular heart rhythms.